Re: C128 256K MMU expansion

From: Marko Mäkelä <msmakela_at_gmail.com>
Date: Wed, 20 Jul 2022 12:46:23 +0300
Message-ID: <YtfO77i12SfH7XiO_at_jyty>
Mon, Jul 18, 2022 at 09:17:42PM +0200, Maciej Witkowiak wrote:
>I found a complete MMU implementation: 
>https://github.com/eriks5/C128_MiSTer/blob/master/rtl/mmu8722.vhd but I 
>have no idea how complex the result is.

Ideally, a 4-bank MMU and enough of a 6821 PIA (for expanding each 64KiB 
bank to 256KiB) would fit in a single device. The extra features could 
be enabled by jumpers on the daughterboard, which would be plugged into 
the MMU socket.

I did not check if it would be technically possible, but it would be 
nice if the entire expansion could be implemented by something that 
would be plugged into the MMU socket. I think that disabling the the 
on-board DRAM would be trivial, by simply never generating any CAS 
signals for them. Some modifications to the main board might be 
necessary to disable or bypass some other things.

	Marko
Received on 2022-07-20 12:00:05

Archive generated by hypermail 2.3.0.